If you have the Auto-mipmap or Auto-tile options enabled by default, a pre-process of the texture will be performed by OIIO in the first render that a texture is used. This will be saved in the texture cache, and the process will not be required in following renders. The drawback of this is that in Windows, textures will be locked after the first render.
- Use the Flush Caches > Textures command.
- Disable the Auto-mipmap and Auto-tile in the render settings while you are modifying textures. With this option, you will not have any preprocess before each render.
Used texture files are locked after a render has been started (even if it is not an IPR session) and they cannot be written by another application such as Photoshop, for example. The typical message that is shown is:
The user then has to close C4D and reopen the scene for C4DtoA to accept the newly saved texture file.
This issue only exists on the Windows platform. MacOS users should be unaffected.
The following workaround is recommended:
The Flush Caches menu can be found within the Arnold menubar.
Select Flush Caches > Textures, and you should then be able to save any edited textures that are associated with any shaders in the currently open scene in C4D. If the texture is connected to a Skydome light or a quad light, then you would select the appropriate menu. Otherwise selecting 'All' will flush all texture caches in the scene.
The Substance Shader is supported by C4DtoA. The plugin writes textures of the substance asset to the tex/substance_cache folder of the project or to the user data folder for material previews. The Flush > Substance texture cache command removes these folders and all textures within.